Vibrator device



Nov. 27, 1956 E. MATTHEWS 2,771,859

VIBRATOR DEVICE Filed OCT.. 27, 1955 lFgn INVENTOR. LYLE E. MATTHEWS VIBRATGR DEVICE Lyle E. Matthews, @anat-d, Calif., assigner to the United States of America as represented by the Secretary of the Navy Application ctoher 27, 1955, Serial No. 543,284

Claims. (Cl. 121-17) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a vibrator device and more particularly to a fluid pressure operated device employing an interconnected piston and valve member which are subjected to different fluid pressures.

There are numerous applications in which vibrator devices are employed as for example in the environmental testing of aircraft components wherein it is desired to simulate the actual operating conditions which equipment may be subjected to in operation. ln such testing applications for which the present invention is particularly suited, it is necessary to provide a device wherein the frequency and amplitude may be varied over wide ranges in order to simulate varying environmental conditions.

Prior art devices have employed arrangements wherein iiuid pressure is utilized as the operating medium, but such devices have proved unsatisfactory due to the complex mechanical valving arrangements thereof which are subject to mechanical failure, and further due to the fact that the frequency and amplitude of the vibratory output of the device is not suiciently adjustable to simulate the desired conditions. The most successful of prior art vi ratory devices have been those wherein electromagnets are utilized to produce the vibrations, and such devices provide an adequate frequency and amplitude range but are far more expensive and bulky in construction than the fluid pressure operated type of vibrator device.

The present invention utilizes an arrangement wherein iluid pressure is utilized to operate the device and the structure thereof is extremely simple, employing merely a hollow cylinder having a piston and an interconnected valve member slidably disposed relative thereto7 and means for introducing uid pressure into the interior of the cylinder. There are no small moving parts in the device and the operation thereof is foolproof and extremely reliable. The device may be operated over a wide range of frequencies and amplitudes thereby substantially duplicating the operation of the prior art electrically operated devices, and yet maintaining the advantage of simplicity and compactness obtainable with fluid pressure operated type vibrators.

An object of the present invention is the provision of a new and novel vibrator device wherein the frequency and amplitude of the vibratory output thereof may be accurately reproduced over a wide variable range.

Another object is to provide a vibratory device which is simple and inexpensive in construction, yet extremely rugged and reliable in operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. l is a longitudinal section of a preferred embodiment of the device, and

2,77l59 Patented Nov. 27, 1956 Fig. 2 is an end view of the device shown in Fig. 1.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the views, there is shown a hollow, cylindrical body means 10 which may be fastened in position by any desired conventional means (not shown). Body member 1d is formed of a suitable metallic material such as steel or the like'and one end 11 thereof is preferably formed of a resilient material such as rubber for a purpose hereinafter disclosed.

A wall 12 extends laterally across an intermediate portion of the interior of the cylinder and has a central opening 13 formed longitudinally therethrough. It is evident that wall 12 divides the interior of the cylinder into two chambers 14 and 15. Radially extending openings 16 and 17 are formed through the outer wall of body member 10 and provide communication between the exterior of the cylinder and the interior of chambers 1li and 15 respectively. Openings 16 and 17 are provided with screw threads and suitable fittings 18 and 19 are threaded therein, the fittings being connected to conduits 20 and 21 respectively which are in communication with sources of duid pressure such as air or the like through suitable Valve means (not shown).

A piston 24 is slidably disposed within the left end portion of the cylinder, the piston having an outer face 25 and an inner face 26; and it is evident that chamber 1d is enclosed between inner face 26 of the piston and face 27 of wall 12. A cylindrical shaft 31 extends through opening 13 of wall 12 and has a slidable lit with the inner surface thereof. Shaft 31 has a longitudinally extending threaded opening formed centrally in the opposite ends thereof, and piston 24 is secured to end portion 30 of the shaft by means of a bolt 28 which extends through a central opening 29 formed in piston 2d and is threaded into the opening in the shaft.

A substantially disk-shaped frapper valve member 32 is secured to the opposite end 33 of shaft 31 by means of a bolt 34 which extends through a central opening 35 formed in apper valve 32 and is threaded into the opening in the shaft. Valve member 32 has an cuter face 3 l and an inner face 37; and as shown in solid lines on the drawing, the apper Valve is in engagement with end 11 of body member 12 thereby sealing and defining chamber 15 between the inner face 37 of the ilapper valve and face 38 of wall 12. Resilient portion 11 is provided to ensure a sealing relationship between flapper valve member 32 and body member 10 such that the iuid pressure within chamber 15 will not escape when valve member 32 is in sealing position. Although a rubber-like material may be employed in portion 11 when the device is to be operated at relatively low frequencies, it is considered preferable to use a resilient metallic substance such as aluminum when it is desired to operate the device at higher frequencies.

It should be noted that the slidable tit of piston 2d with the inner surface of body member 16 and shaft 31 with the inner surface of opening 13 is preferably not a `close tolerance, but is rather loose in order to reduce the frictional losses and enable rapid reciprocation of the piston and liapper valve member, since the amount of loss of uid pressure through the clearances about these components is so insignificant as not to affect the operation of the device.

The :duid introduced through conduit 21 to the interior of chamber 15 must be under greater pressure than the fluid introduced through conduit 2@ into chamber 14. The relative magnitude of the pressures introduced through tubes 20 and 21 may be varied within a wide range to obtain the desired results, the magnitude of the pressure introduced through tube 20 having a greater inuence upon the output frequency of the device, and the magnitude of the pressure of the fluid introduced through conduit 2 having a greater influence upon the output amplitude of the device, although the relative magnitudes of the fluid pressures are interrelated in their effect upon the frequency and amplitude of the output of the device. For example, if it is desired to obtain an output frequency of approximately 20) cycles per second with a device having the relative dimensions shown in the drawing, the fluid introduced through conduit 20 may be under a pressure of l() p. s. i. and the uid introduced through conduit may be under a pressure of 30 p. s. i.

The operation of the device is as follows:

The fluid pressure may be introduced simultaneously through conduits 2li and Z1, but let us assume that fluid pressure at l p. s. i. is initially introduced through conduit 2@ into chamber 14. The fluid pressure acting against face 2o of the piston will force the piston to the left until the inner face 37 of flapper valve member 32. is pressed tightly into sealing engagement with end 11 of the body member 1li. The device will remain in this static condition until fluid pressure is admitted through conduit 21 whereupon the greater pressure within chamber acting against an area which is equal to that against which the fluid pressure in chamber 14 is acting forces the ilapper valve 32, shaft 31 and piston 24 to the right into the phantom line positions shown in the drawing and indicated by reference numerals 32' and 24 respectively. The fluid pressure within .chamber 15 is thereby exhausted to atmosphere and drops below the pressure in chamber 14. The pressure acting against face 26 of piston 24 is then greater than the pressure acting against face 37 of valve member 32 and the piston, shaft and valve member are forced back into the position shown in full lines on the drawing whereupon the fluid pressure in chamber 15 builds back up to a higher value than that in chamber 14 and the piston, shaft and valve member are again forced to the right into the phantom line position.

The above described sequence of operation continues to repeat as long as a higher fluid pressure is introduced into chamber 15 than into chamber 14. It is evident that by suitably varying the pressure within chambers 14 and 15, the operator may control the frequency and amplitude of the vibratory output of the device during operation. The object which it is desired to vibrate may be suitably secured either to piston 24 or flapper valve member 32 as may be desired.

It is apparent from the foregoing that there lis provided a new and novel vibrator device wherein the frequency and amplitude of the vibratory output thereof may be accurately reproduced over a wide range of values. The device is simple and inexpensive in construction, yet extremely rugged and reliable in operation.

Obviously many modifications and Variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

4 lclaim: l. A vibrator device which comprises a hollow body means, means for dividing the interior of said body means into a plurality of chambers, a piston slidably disposed in one of said chambers, valve means for venting another of said chambers to atmosphere, means connected to said piston and said valve means to cause them to move synchrcnously, and means for introducing fluid pressure into said one and said other chambers, the fluid introduced into said other chamber being under greater pressure than tl e fluid introduced into said one chamber.

2. A vibrator device which comprises a hollow cylindrical body means, wall means extending substantially transversely across the interior of said body means and dividing the interior of said body means into two chambers, a piston slidably disposed in a first of said chambers, the second of said chambers being open at one end thereof, valve means for closing the open end of said second chamber, means connecting said piston and said valve means to one another for synchronous movement, means for introducing fluid under pressure into said first chamber, and means for introducing fluid into said second chamber at a greater pressure than the fluid in said first chamber.

3. A device as defined in claim 2 wherein said wall means has an opening formed therethrough, said connecting means comprising al shaft connected at opposite ends thereof to said piston and said valve means, said shaft extending longitudinally through said opening.

4. A vibrator device which comprises a hollow cylindrical body member having a longitudinal axis, a wall extending transversely across Vthe interior of said body member and having opposite faces, said wall having an opening extending longitudinally therethrough, the opposite faces of said wall forming the first ends of each of two chambers Within said body member, a piston slidably disposed within said body member and having inner and outer faces, the inner face of said piston forming the opposite end of the first of said two chambers, a shaft having one end thereof connected to said piston and extending slidably through said opening in said wall, a valve member connected to the opposite end of said shaft and having inner and outer faces, the inner face of said valve member forming the opposite end of the second of said two chambers when said valve member is in sealing position relative to said body member, said piston and valve member being adapted to move` longitudinally with respect to said body member such that said valve member may move out of sealing position venting said second chamber to atmosphere, means for introducing fluid under pressure into said first chamber, and means for introducing fluid into said second chamber at a greater pressure than the fluid in said first chamber.

5. lA device as defined in claim 4 wherein the inner face of said valve member engages one end portion of said body member when the valve member is in sealing position thereby preventing communication between said second chamber and atmosphere.

No references cited. 

